Nearly a year ago, Microsoft and Intel warned users about security vulnerabilities in Intel CPU memory mapped I/O (MMIO). The two companies labelled these flaws as “MMIO Stale Data Vulnerabilities”. Microsoft is now rolling out its mitigations for these vulnerabilities for Windows Server 2016 and Windows 10 version 1507.
Microsoft has already sent out the fix for the supported Windows 10 and Windows 11 build last month. This week's rollout is about catching up to some other versions. If exploited, a threat actor would be able to access sensitive data on a machine.
In the support document that highlights the MMIO Stale Data Vulnerabilities, Microsoft offers the following information:
Intel has released “Intel Processors MMIO Stale Data Advisory”. This security advisory states that potential security vulnerabilities exist in Memory Mapped I/O (MMIO) for some Intel processors which might allow information disclosure.
Intel Platform Update (IPU) 2022.1 that is dated June 2022 contains fixes for security vulnerabilities including Memory-Mapped I/O (MMIO) Side-Channel Attack.”
If you are running Windows 10 version 1507 or Windows Server 2016, the updates/mitigations are available now on the Microsoft Update Catalog.
- KB5019179 – Windows 10 version 1507 – Microsoft Update Catalog
- KB5019182 – Windows Server 2016 – Microsoft Update Catalog
Both updates will put the mitigating DDL files onto your Windows builds. Microsoft is listing the Windows 10 version 1507 file as mcupdate_GenuineIntel.dll (version 10.0.10240.19807) for x86 builds. On Windows Server 2016, the file name is mcupdate_GenuineIntel.dll (version 10.0.14393.5793) for x86 builds and mcupdate_GenuineIntel.dll (version 10.0.14393.5793).
These update should solve any issues and shore up MMIO from attack.
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